Elevated heart rate in cardiovascular diseases: a target for treatment?

Impact of dronedarone on patients with atrial fibrillation and diabetes: A sub-analysis of the ATHENA and EURIDIS/ADONIS studies

AIM

This post hoc analysis evaluated efficacy and safety of dronedarone in atrial fibrillation (AF) and atrial flutter (AFL) patients with/without diabetes.

METHODS

Patients were categorized according to baseline diabetes status. Time-to-event analyses were performed using Kaplan-Meier method. Hazard-ratios were assessed using Cox models.

RESULTS

945/4628 (dronedarone = 482; placebo = 463) patients in ATHENA and 215/1237 (dronedarone = 148; placebo = 67) patients in EURIDIS/ADONIS studies had diabetes. In ATHENA, there were higher rates of CV hospitalization/death in patients with diabetes (39.5%) than without diabetes (34.7%). Incidence of first CV hospitalization/death was lower in patients with diabetes treated with dronedarone (35.1%) than placebo (44.1%), and time to this event was longer in those treated with dronedarone than placebo (log-rank p = 0.005). Median AF/AFL recurrence time was longer in patients treated with dronedarone than placebo in patients with diabetes (ATHENA: 722 vs 527 days, log-rank p = 0.004; EURIDIS/ADONIS: 100 vs 23 days, log-rank p = 0.15) or without diabetes (ATHENA: 741 vs 492 days, log-rank p < 0.0001; EURIDIS/ADONIS: 120 vs 59 days, log-rank p = 0.0002). Occurrence of any treatment-related adverse events with dronedarone was similar for patients with/without diabetes and was comparable to placebo.

CONCLUSIONS

Dronedarone reduced incidence of CV hospitalization/death, AF/AFL recurrence and increased time to these events in AF/AFL patients with/without diabetes.

TRIAL REGISTRATION

Not applicable, as it was a post hoc analysis. This article is based on previously conducted studies (ATHENA: NCT00174785, EURIDIS: NCT00259428, and ADONIS: NCT00259376).

Conventional and Bidirectional Genetic Evidence on Resting Heart Rate and Cardiometabolic Traits

CONTEXT

Observational studies have suggested that higher resting heart rate (RHR) may be associated with increased cardiometabolic risk. However, causal associations are not fully understood.

OBJECTIVE

We aimed to examine the direction, strength, and causality of the associations of RHR with cardiometabolic traits.

METHODS

We assessed the strength of associations between measured RHR and cardiometabolic traits in 506 211 and 372 452 participants from China Kadoorie Biobank (CKB) and UK Biobank (UKB). Mendelian randomization (MR) analyses were used to make causal inferences in 99 228 and 371 508 participants from CKB and UKB, respectively.

RESULTS

We identified significant directionally concordant observational associations between RHR and higher total cholesterol, triglycerides (TG), low-density lipoprotein, C-reactive protein (CRP), glucose, body mass index, waist-hip ratio (WHR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) after the Bonferroni correction. MR analyses showed that 10 beat/min higher genetically predicted RHR was trans-ethnically associated with a higher DBP (beta 2.059 [95% CI 1.544, 2.574] mmHg in CKB; 2.037 [1.845, 2.229] mmHg in UKB), higher CRP (0.180 [0.057, 0.303] log mg/L in CKB; 0.154 [0.134, 0.174] log mg/L in UKB), higher TG (0.052 [-0.009, 0.113] log mmol/L in CKB; 0.020 [0.010, 0.030] log mmol/L in UKB) and higher WHR (0.218 [-0.033, 0.469] % in CKB; 0.225 [0.111, 0.339] % in UKB). In the opposite direction, higher genetically predicted SBP, TG, glucose, and WHR, and lower high-density lipoprotein, were associated with elevated RHR.

CONCLUSION

Our large-scale analyses provide causal evidence for associations between RHR and cardiometabolic traits, highlighting the importance of monitoring heat rate as a means of alleviating the adverse effects of metabolic disorders.

Moderate heart rate reduction promotes cardiac regeneration through stimulation of the metabolic pattern switch

As a biological pump, the heart needs to consume a substantial amount of energy to maintain sustained beating. Myocardial energy metabolism was recently reported to be related to the loss of proliferative capacity in cardiomyocytes (CMs). However, the intrinsic relationship between beating rate and proliferation in CMs and whether energy metabolism can regulate this relationship remains unclear. In this study, we find that moderate heart rate reduction (HRR) induces CM proliferation under physiological conditions and promotes cardiac regenerative repair after myocardial injury. Mechanistically, moderate HRR induces G1/S transition and increases the expression of glycolytic enzymes in CMs. Furthermore, moderate HRR induces a metabolic pattern switch, activating glucose metabolism and increasing the relative proportion of ATP production by the glycolytic pathway for biosynthesis of substrates needed for proliferative CMs. These results highlight the potential therapeutic role of HRR in not only acute myocardial protection but also long-term CM restoration.

Association Between Heart Rate and Major Adverse Cardiovascular Events Among 9,991 Hypertentive Patients: A Multicenter Retrospective Follow-Up Study

Objective: To assess the effect of heart rate at baseline on major adverse cardiovascular events (MACEs) among hypertensive patients in China. Methods: A multicenter retrospective study was conducted with a 24 month follow-up period. A total of 10,031 hypertensive patients treated with standard antihypertensive drugs were grouped according to their heart rate before treatment: <65 beats per min (bpm), 65-69 bpm, 70-74 bpm, 75-79 bpm, and ≥80 bpm. The occurrence of any of MACEs was as the endpoint event during the 24 month follow-up period. The effect of heart rate at baseline on MACEs was analyzed using univate and multivariable Cox proportional regression analyses, with hazard ratios (HRs) and 95% confidence intervals (CIs). The restricted cubic spline (RCS) model was used to fit the Cox proportional harzard model with 5 knots at the 5^th, 25^th, 50^th, 75^th, and 95^th percentiles of heart rate. Results: Totally 9,991 patients were finally enrolled with the mean systolic pressure (SBP)/diastolic pressure (DBP) of 130.59 ± 7.13/77.66 ± 5.99 mmHg at 24 month follow-up. The incidence of MACEs was 4.80% (n = 480). After adjustment for age, gender, baseline blood pressure, alcohol drinking, smoking, hyperlipidemia, diabetes, coronary heart disease, cerebrovascular disease and antihypertensive drug use, patients with heart rate <65 bpm (HR = 1.450, 95% CI: 1.098-1.915) and ≥80 bpm (HR = 1.391, 95% CI: 1.056-11.832) showed 0.45 fold and 0.391 fold increases of MACE risks, compared with patients with heart rate of 70-74 bpm. Furthermore, MACE risks were increased by 86.0% and 65.4% in men, and 59.3% and 69.0% in elderly patients aged ≥65 years at heart rate <65 bpm or ≥80 bpm, respectively. We also found a non-liner U-shaped correlation between heart rate and the occurrence of MACEs. Conclusions: Heart rate might be an independent risk factor for MACEs in hypertensive patients. An appropriate range of heart rate control may offer guidance to hypertension treatment.

Sudden cardiac death among Iranian population: a two decades follow-up of Tehran lipid and glucose study

Sudden cardiac death (SCD) is described as death within one hour, if observed, from the onset of symptoms, and within 24 h of being alive and well if not observe. Study population includes 3705 men and 4446 women, aged ≥ 30 years. Multivariable Cox proportional hazard models were used to determine the risk factors associated with SCD. After a median follow-up of 17.9 years, 244 SCD (165 in males) occurred. The age-standardized incidence rate (95% confidence intervals (CI)) of SCD was 2.3 (2.1–2.7) per 1000 person-year. Current smoking [Hazard ratio (HR): 2.43, 95% CI: 1.73–3.42], high waist circumference [1.49: 1.04–2.12], hypertension [1.39: 1.05–1.84], type 2 diabetes mellitus [2.78: 2.09–3.69], pulse rate ≥ 90 beats per/minute [1.72: 1.22–2.42] and prevalent cardiovascular disease [1.75: 1.26–2.45] were significant risk factors. The corresponding population attributed fractions (PAF) were 14.30, 16.58, 14.03, 19.60, 7.62, and 8.30, respectively. Being overweight [0.58: 0.40–0.83] and obese [0.61: 0.38–0.98] decreased the risk of SCD. After excluding known diabetes cases from our data analysis, the newly diagnosed diabetes still showed an HR of 2.0 (1.32–3.00) with a PAF of 7.15% in the full adjustment model. To deal with sudden death as a catastrophic outcome, multi-component strategies by policy health makers are suggested.

Diabetic kidney disease in type 2 diabetes: a review of pathogenic mechanisms, patient-related factors and therapeutic options

The global prevalence of diabetic kidney disease is rapidly accelerating due to an increasing number of people living with type 2 diabetes. It has become a significant global problem, increasing human and financial pressures on already overburdened healthcare systems. Interest in diabetic kidney disease has increased over the last decade and progress has been made in determining the pathogenic mechanisms and patient-related factors involved in the development and pathogenesis of this disease. A greater understanding of these factors will catalyse the development of novel treatments and influence current practice. This review summarises the latest evidence for the factors involved in the development and progression of diabetic kidney disease, which will inform better management strategies targeting such factors to improve therapeutic outcomes in patients living with diabetes.

Chenodeoxycholic and deoxycholic acids induced positive inotropic and negative chronotropic effects on rat heart

Bile acids are endogenous amphiphilic steroids from the metabolites of cholesterol. Studies showed that they might contribute to the pathogenesis of cardiopathy in cholestatic liver diseases. Chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA) is associated with colon cancer, gallstones, and gastrointestinal disorders. However, little information is available regarding their cardiac effects. Here, we reported that CDCA (100 μM) and DCA (100 μM) significantly increased the left ventricular developed pressure of the isolated rat hearts to 122.3 ± 5.6% and 145.1 ± 13.7%, and the maximal rate of the pressure development rising and descending (± dP/dtmax) to 103.4 ± 17.6% and 124.4 ± 37.7% of the basal levels, respectively. They decreased the heart rate and prolonged the RR, QRS, and QT intervals of Langendorff-perfused hearts in a concentration-dependent manner. Moreover, CDCA and DCA increased the developed tension of left ventricular muscle and the cytosolic Ca2+ concentrations in left ventricular myocytes; these functions positively coordinated with their inotropic effects on hearts. Additionally, CDCA (150 μM) and DCA (100 μM) decreased the sinoatrial node beating rate to 80.6 ± 3.0% and 79.7 ± 0.9% of the basal rate (334.2 ± 10.7 bpm), respectively. These results were consistent with their chronotropic effects. In conclusion, CDCA and DCA induced positive inotropic effects by elevating the Ca2+ in left ventricular myocytes. They exerted negative chronotropic effects by lowering the pace of the sinoatrial node in rat heart. These results indicated that the potential role of bile acids in cardiopathy related to cholestasis.

Increased heart rate with sleep disordered breathing in hypertrophic cardiomyopathy

BACKGROUND

Current guidelines recommend medications with rate control properties for symptomatic patients with hypertrophic cardiomyopathy (HCM) based on the rationale that lowering heart rate (HR) improves their symptoms. Whether sleep disordered breathing (SDB) is associated with increased HR in HCM patients is not known.

METHOD

We diagnosed uncontrolled SDB (oxygen desaturation index ≥5) in consecutive echocardiographically confirmed HCM patients seen at Mayo Clinic, Rochester, and analyzed their HR as recorded by a 24-h Holter monitor. We compared mean, minimum, maximum HR between those with vs without SDB. In a pilot subanalysis of HCM patients with SDB who also underwent subsequent diagnostic polysomnography (PSG), we analyzed RR interval changes coinciding with obstructive sleep apnea and hypopnea episodes.

RESULTS

Of the 230 HCM patients included in this study (age 54 ± 16 years; 138 male; LVOT pressure gradient at rest 45 ± 39 mmHg), 115 (50%) patients had SDB. HCM patients with SDB were recorded to have higher mean HR (71 vs. 67 bpm; p = .002, adjusted p = .001), and this difference was most pronounced during night hours of 10 PM to 5 AM (61 vs. 67 bpm; p < .001). In the pilot analysis of the available PSG data, the release of obstructive sleep apneas and hypopneas coincided with fluctuation of HR.

CONCLUSIONS

SDB is independently associated with higher mean HR in patients with HCM, and this difference is most significant during sleep. Treatment of SDB, which is readily available, should be tested as a complementary modality to the currently recommended pharmacotherapy aimed at lowering HR in patients with symptomatic HCM.

Direct evidence of bradycardic effect of omega-3 fatty acids acting on nucleus ambiguus

Docosahexaenoic acid (DHA) an omega-3 polyunsaturated fatty acid, is an agonist of FFA1 receptor. DHA administration reduces the heart rate via unclear mechanisms. We examined the effect of DHA on neurons of nucleus ambiguus that provide the parasympathetic control of heart rate. DHA produced a dose-dependent increase in cytosolic Ca²⁺ concentration in cardiac-projecting nucleus ambiguus neurons; the effect was prevented by GW1100, a FFA1 receptor antagonist. DHA depolarized cultured nucleus ambiguus neurons via FFA1 activation. Bilateral microinjection of DHA into nucleus ambiguus produced bradycardia in conscious rats. Our results indicate that DHA decreases heart rate by activation of FFA1 receptor on cardiac-projecting nucleus ambiguus neurons.

Age, sex and disease-specific associations between resting heart rate and cardiovascular mortality in the UK BIOBANK

OBJECTIVE

To define the sex, age, and disease-specific associations of resting heart rate (RHR) with cardiovascular and mortality outcomes in 502,534 individuals from the UK Biobank over 7-12 years of prospective follow-up.

METHODS

The main outcomes were all-cause, cardiovascular, and ischaemic heart disease mortality. Additional outcomes included incident acute myocardial infarction (AMI), fatal AMI, and cancer mortality. We considered a wide range of confounders and the effects of competing hazards. Results are reported as hazard ratios (HR) for all-cause mortality and sub-distribution hazard ratios (SHR) for other outcomes with corresponding 95% confidence intervals (CI) per 10bpm increment of RHR.

RESULTS

In men, for every 10bpm increase of RHR there was 22% (HR 1.22, CI 1.20 to 1.24, p = 3×10-123) greater hazard of all-cause and 17% (SHR 1.17, CI 1.13 to 1.21, p = 5.6×10-18) greater hazard of cardiovascular mortality; for women, corresponding figures were 19% (HR 1.19, CI 1.16 to 1.22, p = 8.9×10-45) and 14% (SHR 1.14, CI 1.07 to 1.22, p = 0.00008). Associations between RHR and ischaemic outcomes were of greater magnitude amongst men than women, but with similar magnitude of association for non-cardiovascular cancer mortality [men (SHR 1.18, CI 1.15-1.21, p = 5.2×10-46); women 15% (SHR 1.15, CI 1.11-1.18, p = 3.1×10-18)]. Associations with all-cause, incident AMI, and cancer mortality were of greater magnitude at younger than older ages.

CONCLUSIONS

RHR is an independent predictor of mortality, with variation by sex, age, and disease. Ischaemic disease appeared a more important driver of this relationship in men, and associations were more pronounced at younger ages.

Is Heart Rate a Confounding Factor for Photoplethysmography Markers? A Systematic Review

Finger photoplethysmography (PPG) waveform is blood volume change of finger microcirculation that reflects vascular function. Reflection index (RI), stiffness index (SI) and second derivative of photoplethysmogram (SDPPG) are derived from PPG waveforms proposed as cardiovascular disease (CVD) markers. Heart rate (HR) is a known factor that affects vascular function. Individual resting HR variation may affect RI, SI and SDPPG. This review aims to identify studies about the relationship between HR with RI, SI and SDPPG among humans. A literature search was conducted in Medline via the Ebscohost and Scopus databases to find relevant articles published within 11 years. The main inclusion criteria were articles in the English language that discuss the relationship between HR with RI, SI and SDPPG using PPG among humans. The search found 1960 relevant articles but only six articles that met the inclusion criteria. SI and RI showed an association with HR. SDPPG (SDPPG-b/SDPPG-a ratio, SDPPG-d/SDPPG-a ratio, aging index (AGI) and revised aging index (RAGI)) also had an association with HR. Only RI had a considerable association with HR, the association between SI and HR was non-considerable and the association between HR and SDPPG was inconclusive. Further interventional studies should be conducted to investigate this issue, as a variation in resting HR may challenge the validity of PPG-based CVD markers.

Risk Factor Variability and Cardiovascular Outcome: JACC Review Topic of the Week

Until recently, intraindividual visit-to-visit variability of cardiovascular risk factors has been dismissed as random fluctuation. This simplistic concept was challenged by demonstrating that visit-to-visit blood pressure variability, independent of average blood pressure, was a powerful risk factor for stroke. Subsequently, variability of other cardiovascular risk factors such as cholesterol, glycemia, and body weight was documented to increase risk independent of their absolute values. Variability of these risk factors has been demonstrated to be a powerful predictor for all-cause and cardiovascular mortality, stroke, coronary artery disease, heart failure, end-stage renal disease, and dementia. With the notable exception of heart rate, cardiovascular risk factors must now be defined by 2 components: the magnitude and duration of sustained risk factor elevation and, equally important, the variability of the same risk factor over time.

Association of resting heart rate and its change with incident cardiovascular events in the middle-aged and older Chinese

Whether heart rate change is associated with cardiovascular disease (CVD) in the general population is unclear. We conducted a prospective cohort study to assess the association of resting heart rate and its change with incident CVD in the middle-aged and older Chinese. Resting heart rate was measured during the baseline survey (September 2008 to June 2010) and the resurvey (2013). Incident CVD was followed up until December 31, 2016. Finally, a total of 20,828 participants were included in the analyses of baseline heart rate and 9132 participants were included in the analyses of heart rate change. The associations of baseline heart rate and heart rate change with incident CVD were assessed with multivariable Cox proportional hazards models. Compared with moderate baseline heart rate (65 to 80 bpm), low baseline heart rate (<65 bpm) was associated with higher risk of CVD (HR, 1.19; 95% CI, 1.07–1.32). Compared with stable heart rate (−5 to 15 bpm) in the moderate baseline heart rate group (65 to 80 bpm), an increase of heart rate (>15 bpm) in high baseline heart rate group (>80 bpm) (HR, 1.67; 95% CI, 1.02–2.71) or a decrease of heart rate (<−5 bpm) in low baseline heart rate group (<65 bpm) (HR, 2.48; 95% CI, 1.27–4.82) was associated with higher risk of CVD. In conclusion, low resting heart rate is associated with higher risk of CVD. Both continuous increase in high baseline heart rate and decrease in low baseline heart rate are associated with higher risk of CVD.

Impact of changes in heart rate with age on all-cause death and cardiovascular events in 50-year-old men from the general population

Background

Resting heart rate (RHR), a known cardiovascular risk factor, changes with age. However, little is known about the association between changes in RHR and the risk of cardiovascular events. The purpose of this study was therefore to assess the impact of RHR at baseline, and the change in RHR over time, on the risk of all-cause death and cardiovascular events.

Design

A random population sample of men born in 1943 who were living in Gothenburg, Sweden was prospectively followed for a 21-year period.

Methods

Participants were examined three times: first in 1993 and then re-examined in 2003 and 2014. At each visit, a clinical examination, an ECG and laboratory analyses were performed. Change in RHR between 1993 and 2003 was defined as a decrease if RHR decreased by 5 beats per minute (bpm), an increase if RHR increased by 5 bpm or stable if the RHR change was <4bpm).

Results

Participants with a baseline RHR of >75 bpm in 1993 had about a twofold higher risk of all-cause death (HR 2.3, CI 1.2 to 4.7, p=0.018), cardiovascular disease (CVD) (HR 1.8, CI 1.1 to 3.0, p=0.014) and coronary heart disease (CHD) (HR 2.2, CI 1.1 to 4.5, p=0.025) compared with those with <55 bpm in 1993. Participants with a stable RHR between 1993 and 2003 had a 44% decreased risk of CVD (HR 0.56, CI 0.35 to 0.87, p=0.011) compared with participants with an increasing RHR. Furthermore, every beat increase in heart rate from 1993 was associated with a 3% higher risk for all-cause death, 1% higher risk for CVD and 2% higher risk for CHD.

Conclusion

High RHR was associated with an increased risk of death and cardiovascular events in men from the general population. Moreover, individuals with an increase in RHR between 50 and 60 years of age had worse outcome.

Elevated preoperative heart rate associated with increased risk of cardiopulmonary complications after resection for lung cancer

BACKGROUND

The study aimed to assess whether preoperative resting heart rate could be a risk factor for cardiopulmonary complications (CPCs) after lung cancer resection.

METHODS

Eligible consecutive patients who underwent resection surgery for non-small cell lung cancer (NSCLC) at Ningbo NO.2 Hospital between May, 2010 and July, 2015 were included. The demographic, clinical characteristics and laboratory parameters were compared in patients with or without CPCs within postoperative 30 days. The multivariate logistic regression analysis was used to analyze the association between CPCs and risk factors. Receiver operating characteristic (ROC) curve analysis was utilized for the predictive role of preoperative resting heart rate for CPCs.

RESULTS

One hundred eighty participants were enrolled into the final analysis and 42 of them had an established diagnosis of CPCs within postoperative 30 days. Elevated preoperative resting heart rate was an independent risk factor for postoperative CPCs (OR: 4.48, 95% CI: 1.17-18.42, P = 0.021) by the multivariate logistic regression analysis. ROC curve analysis indicated elevated resting heart rate as a predictor for CPCs with a cut-off value of 86 beats/min (AUC: 0.813, specificity: 80.95%, sensitivity: 72.46%, P < 0.001).

CONCLUSIONS

Elevated preoperative resting heart rate was associated with an increased risk of postoperative CPCs in patients after resection for lung cancer.

Association between resting heart rate and coronary artery disease, stroke, sudden death and noncardiovascular diseases: a meta-analysis

BACKGROUND

Resting heart rate is linked to risk of coronary artery disease, stroke, sudden death and noncardiovascular diseases. We conducted a meta-analysis to assess these associations in general populations and in populations of patients with hypertension or diabetes mellitus.

METHODS

We searched PubMed, Embase and MEDLINE from inception to Mar. 5, 2016. We used a random-effects model to combine study-specific relative risks (RRs). We used restricted cubic splines to assess the dose-response relation.

RESULTS

We included 45 nonrandomized prospective cohort studies in the meta-analysis. The multivariable adjusted RR with an increment of 10 beats/min in resting heart rate was 1.12 (95% confidence interval [CI] 1.09-1.14) for coronary artery disease, 1.05 (95% CI 1.01-1.08) for stroke, 1.12 (95% CI 1.02-1.24) for sudden death, 1.16 (95% CI 1.12-1.21) for noncardiovascular diseases, 1.09 (95% CI 1.06-1.12) for all types of cancer and 1.25 (95% CI 1.17-1.34) for noncardiovascular diseases excluding cancer. All of these relations were linear. In an analysis by category of resting heart rate (< 60 [reference], 60-70, 70-80 and > 80 beats/min), the RRs were 0.99 (95% CI 0.93-1.04), 1.08 (95% CI 1.01-1.16) and 1.30 (95% CI 1.19-1.43), respectively, for coronary artery disease; 1.08 (95% CI 0.98-1.19), 1.11 (95% CI 0.98-1.25) and 1.08 (95% CI 0.93-1.25), respectively, for stroke; and 1.17 (95% CI 0.94-1.46), 1.31 (95% CI 1.12-1.54) and 1.57 (95% CI 1.39-1.77), respectively, for noncardiovascular diseases. After excluding studies involving patients with hypertension or diabetes, we obtained similar results for coronary artery disease, stroke and noncardiovascular diseases, but found no association with sudden death.

INTERPRETATION

Resting heart rate was an independent predictor of coronary artery disease, stroke, sudden death and noncardiovascular diseases over all of the studies combined. When the analysis included only studies concerning general populations, resting heart rate was not associated with sudden death.

Resting Heart Rate Does Not Predict Cardiovascular and Renal Outcomes in Type 2 Diabetic Patients

Elevated resting heart rate (RHR) has been associated with increased risk of mortality and cardiovascular events. Limited data are available so far in type 2 diabetic (T2DM) subjects with no study focusing on progressive renal decline specifically. Aims of our study were to verify RHR as a simple and reliable predictor of adverse disease outcomes in T2DM patients. A total of 421 T2DM patients with variable baseline stage of diabetic kidney disease (DKD) were prospectively followed. A history of the cardiovascular disease was present in 81 (19.2%) patients at baseline, and DKD (glomerular filtration rate < 60 mL/min or proteinuria) was present in 328 (77.9%) at baseline. Progressive renal decline was defined as a continuous rate of glomerular filtration rate loss ≥ 3.3% per year. Resting heart rate was not significantly higher in subjects with cardiovascular disease or DKD at baseline compared to those without. Using time-to-event analyses, significant differences in the cumulative incidence of the studied outcomes, that is, progression of DKD (and specifically progressive renal decline), major advanced cardiovascular event, and all-cause mortality, between RHR </≥65 (arbitrary cut-off) and 75 (median) bpm were not found. We did not ascertain predictive value of the RHR for the renal or cardiovascular outcomes in T2DM subjects in Czech Republic.

Effects of 12 weeks of treatment with fermented milk on blood pressure, glucose metabolism and markers of cardiovascular risk in patients with type 2 diabetes: a randomised double-blind placebo-controlled study

OBJECTIVE

Studies have indicated a blood pressure (BP)-lowering effect of milk-derived peptides in non-diabetic individuals, but the cardiometabolic effects of such peptides in patients with type 2 diabetes (T2D) are not known. We investigated the effect of milk fermented with Lactobacillus helveticus on BP, glycaemic control and cardiovascular risk factors in T2D.

DESIGN

A randomised, double-blinded, prospective, placebo-controlled study.

METHODS

In one arm of a factorial study design, 41 patients with T2D were randomised to receive 300 ml milk fermented with L. helveticus (Cardi04 yogurt) (n=23) or 300 ml artificially acidified milk (placebo yogurt) (n=18) for 12 weeks. BPs were measured over 24-h, and blood samples were collected in the fasting state and during a meal test before and after the intervention.

RESULTS

Cardi04 yogurt did not reduce 24-h, daytime or nighttime systolic or diastolic BPs compared with placebo (P>0.05). Daytime and 24-h heart rate (HR) were significantly reduced in the group treated by Cardi04 yogurt compared with the placebo group (P<0.05 for both). There were no differences in HbA1c, plasma lipids, C-reactive protein, plasminogen activator inhibitor-1, tumour necrosis factor alpha, tissue-type plasminogen activator: Ag, and von Willebrand factor: Ag between the groups. The change in fasting blood glucose concentration differed significantly between the two groups with a larger increase in the placebo group (P<0.05).

CONCLUSIONS

Ingestion of milk fermented with L. helveticus compared with placebo for 12 weeks did not significantly reduce BP in patients with T2D. Our finding of lower HRs and fasting plasma glucose levels in T2D patients during ingestion of fermented milk needs further validation.

Bradycardia is associated with future cardiovascular diseases and death in men from the general population

BACKGROUND

Although a higher heart rate is known to be a risk factor for cardiovascular disease (CVD) events, there have been no reports concerning bradycardia. Whether lower and higher resting pulse rates (RPRs) are associated with cardiovascular risk was investigated in subjects from a community-based, prospective cohort study.

METHODS

After subjects with atrial fibrillation, subjects with a history of CVD, and subjects receiving antihypertensive treatment were excluded, 17,766 subjects (5958 men), aged 40-79 (mean 61.5) years, were analyzed. The RPR at baseline was categorized into four groups (RPR<60, 60-69.5, 70-79.5, ≥80 beats per minute (bpm)) using the average value of two consecutive measurements. The endpoint was set as the composite outcome of myocardial infarction, stroke, or sudden death.

RESULTS

During a mean follow-up of 5.6 years, there were 213 events in men and 186 events in women. In Cox regression models, increased risks of CVD were found in the men group with RPR<60 bpm, as well as the group with RPR≥80 bpm, compared with the reference group with RPR 60-69.5 bpm (hazard ratio [HR] = 1.73, p = 0.005 and HR = 2.01, p < 0.001). These increased risks were found even when adjusted for age and other CVD risk factors (HR = 1.55, p = 0.026 with RPR<60 bpm and HR = 1.72, p = 0.009 with RPR≥80 bpm). In women, there were no significant associations between RPR and CVD risk.

CONCLUSION

Bradycardia, as well as a higher pulse rate, may be an independent risk factor for future cardiovascular events in apparently healthy men.

High long-chain n-3 fatty acid intake attenuates the effect of high resting heart rate on cardiovascular mortality risk: a 24-year follow-up of Japanese general population

BACKGROUND

Increased resting heart rate (RHR) independently predicts cardiovascular mortality. Meanwhile, long-chain n-3 fatty acids (LCn3FAs) have a cardioprotective effect. Our aim was to evaluate whether higher LCn3FAs intake attenuates the elevated risk of cardiovascular mortality associated with increased RHR.

METHODS

We conducted a population-based 24-year prospective cohort study of Japanese, whose LCn3FAs intake is relatively high. Study participants included 8807 individuals aged 30-95 years from randomly selected areas across Japan without cardiovascular diseases and anti-hypertensive drugs at baseline. The primary endpoint was cardiovascular mortality, and the secondary endpoints were cardiac and stroke mortality during 24 years of follow-up. Individual dietary LCn3FAs intake was estimated from household-based 3-day weighed food records. RHR was obtained from 3 consecutive R-wave intervals on 12-lead electrocardiography. Cox models were used to estimate the multivariable hazard ratios (HRs) and 95% confidence intervals (95% CIs) adjusting for possible confounders.

RESULTS

During the follow-up period, 617 cardiovascular deaths were observed. The median daily intake of LCn3FAs was 0.37% kcal (0.86g/day). The interaction between dietary LCn3FAs intake and RHR in the risk of cardiovascular mortality was statistically significant (p=0.033). The risk of cardiovascular mortality was significantly higher in the low-intake group (<0.37%kcal) with an RHR >85beats/min (bpm) [hazard ratio (HR), 1.67; 95% confidence interval (CI), 1.15-2.43], but not in the high-intake group (≥0.37%kcal) with an RHR >85bpm (HR, 0.92; 95% CI, 0.61-1.38), compared with those in the high-intake group with an RHR <70bpm. Similar results were observed with stroke mortality, but not with cardiac mortality.

CONCLUSIONS

The risk of cardiovascular mortality associated with increased RHR is elevated in participants with low dietary LCn3FAs intake, but not in participants with high dietary LCn3FAs intake in a representative Japanese general population. These results suggest that high dietary LCn3FAs intake may prevent cardiovascular mortality associated with increased RHR.

Heart rate as a possible therapeutic guide for the prevention of cardiovascular disease

Epidemiologic evidence indicates that an elevated heart rate (HR) is an independent predictor of all-cause and cardiovascular (CV) mortality. Ivabradine, a pure HR-lowering agent, reduces CV events in patients with coronary artery disease (CAD) and chronic heart failure, and indicate that an HR greater than 70 b.p.m. is hazardous. These findings demonstrate not only that an elevated HR is an epiphenomenon of CV risk status but also that an elevated HR itself should be a therapeutic target. In addition, recent epidemiologic evidence demonstrates that the in-treatment HR or HR change predicts subsequent all-cause and CV mortality, independent of the HR-lowering strategy. Characteristics of the in-treatment HR or HR change are also important as possible therapeutic guides for risk management. However, there have been concerns regarding deleterious effects on CV event prevention owing to β-blocker-derived pharmacologic HR reduction. The potential role of HR and its modulation should be considered in future guidance documents.

[Resting heart rate and cardiovascular disease]

Heart rate reflects autonomic nervous system activity. Numerous studies have demonstrated that an increased heart rate at rest is associated with cardiovascular morbidity and mortality as an independent risk factor. It has been shown a link between cardiac autonomic balance and inflammation. Thus, an elevated heart rate produces a micro-inflammatory response and is involved in the pathogenesis of endothelial dysfunction. In turn, decrease in heart rate produces benefits in congestive heart failure, myocardial infarction, atrial fibrillation, obesity, hyperinsulinemia, insulin resistance, and atherosclerosis. Alteration of other heart rate-related parameters, such as their variability and recovery after exercise, is associated with risk of cardiovascular events. Drugs reducing the heart rate (beta-blockers, calcium antagonists and inhibitors of If channels) have the potential to reduce cardiovascular events. Although not recommended in healthy subjects, interventions for reducing heart rate constitute a reasonable therapeutic goal in certain pathologies.

Improved Hypertension Control with the Imidazoline Agonist Moxonidine in a Multinational Metabolic Syndrome Population: Principal Results of the MERSY Study

This study was designed to assess the effects of moxonidine on blood pressure and aspects of the metabolic syndrome in racially diverse population of patients encountered in routine medical practice. Physicians collected data on a minimum of three consecutive patients with uncontrolled essential hypertension and criteria for metabolic syndrome, eligible to receive moxonidine (0.2-0.4 mg once daily) for 6 months, either as monotherapy or as adjunct therapy to current antihypertensive treatment. Systolic and diastolic blood pressure (BP) declined by an average of 24.5 + 14.3 mmHg and 12.6 + 9.1 mmHg, respectively. BP responder rates defined as attaining BP < 140/90 mmHg were significantly (P < 0.001) and substantially higher among younger patients, nonpostmenopausal women, and patients receiving monotherapy. While potentially relevant improvements in the entire cohort were observed in regard to body weight (-2.1 ± 5.4 kg), fasting plasma glucose (from 6.8 to 6.2 mmol/L), and triglycerides (2.4 to 2.0 mmol/L), statistically significant changes in metabolic parameters could only be detected in subgroup analyses. Moxonidine therapy reduced blood pressure and improved rates of blood pressure control in this group of patients. While the observed trend towards improvement in various metabolic parameters merits further investigation, the overall effect of moxonidine treatment is consistent with a reduction of total cardiovascular risk in this hypertensive metabolic syndrome cohort.

Prognostic significance of baseline heart rate and its interaction with beta-blocker use in resistant hypertension: a cohort study

BACKGROUND

The prognostic significance of heart rate (HR) and its relationship with beta-blocker use are controversial and have never been evaluated in resistant hypertension.

METHODS

In a prospective study, 528 patients with resistant hypertension had HR measured on clinical examination, electrocardiography (ECG), and during ambulatory blood pressure monitoring. Primary endpoints were a composite of fatal and nonfatal cardiovascular events, all-cause and cardiovascular mortality. Multivariable Cox regression was used to assess the associations between slow HR (< 60 bpm or < 55 bpm for nighttime HR) and fast HR (> 75 bpm or > 70 bpm for nighttime HR) and the occurrence of endpoints in relation to the reference middle HR (60-75 bpm) subgroup.

RESULTS

After a median follow-up of 4.8 years, 62 patients died, 44 from cardiovascular causes; and 94 cardiovascular events occurred. Fast and slow HRs were mainly predictors of mortality, and ambulatory HRs were more significant risk markers than clinic or ECG HR. A slow 24-hour HR was a predictor of the composite endpoint (hazard ratio, 2.0; 95% confidence interval [CI], 1.2-3.4), whereas both slow and fast ambulatory HRs were predictors of cardiovascular mortality (hazard ratio, 2.3; 95% CI, 1.1-5.1). Four hundred and seventeen patients (79%) were using beta-blockers and this affected the HR prognostic value. A fast HR was a more significant risk marker in patients using beta-blockers, whereas a slow HR was a predictor mainly in those not using beta-blockers.

CONCLUSIONS

There is an overall U-shaped relationship between HRs, particularly when measured during ambulatory monitoring, and prognosis in resistant hypertension. A fast HR is a significant predictor in patients using beta-blockers, while a slow heart rate is a more important predictor in those not using beta-blockers.

Blood pressure tracking over the adult life course: patterns and correlates in the Framingham heart study

The extent to which select vascular risk factors differentially influence blood pressure (BP) is incompletely understood. Thus, we used multilevel modeling to analyze serial BP measurements using 21 732 person-observations obtained on Framingham Heart Study participants (mean age, 38 years, 52% women; 4993 unique individuals) over a 28-year period. We related longitudinal tracking of each BP measure (systolic BP, diastolic BP, mean arterial pressure, and pulse pressure) to age, sex, body mass index, smoking, diabetes mellitus, total/high-density lipoprotein cholesterol ratio, and heart rate. In multivariable-adjusted analyses, we observed that older age, male sex, greater body mass index, and higher heart rate were positively associated with increase in all BP measures (P<0.0001). Notably, higher total/high-density lipoprotein cholesterol ratio was associated with greater mean arterial pressure (P<0.01). Conversely, diabetes mellitus and smoking were associated with higher pulse pressure (P<0.01). We also observed effect modification by sex: the increase in pulse pressure with age and body mass index was more pronounced in women compared with men (P<0.0001). All BP measures tracked at higher levels in both men and women with multiple vascular risk factors. Taken together, our longitudinal observations in a large community-based sample demonstrate a greater pulsatile load in women than in men with increasing age. We also observed a differential impact of select vascular risk factors on the individual components of BP, underscoring distinct regulation of these measures over the life course.

Resting heart rate and the risk of microvascular complications in patients with type 2 diabetes mellitus

Background

A higher resting heart rate is associated with an increased probability of cardiovascular complications and premature death in patients with type 2 diabetes mellitus. The impact of heart rate on the risk of developing microvascular complications, such as diabetic retinopathy and nephropathy, is, however, unknown. The present study tests the hypothesis that a higher resting heart rate is associated with an increased incidence and a greater progression of microvascular complications in patients with type 2 diabetes mellitus.

Methods and Results

The relation between baseline resting heart rate and the development of a major microvascular event was examined in 11 140 patients who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) study. Major microvascular events were defined as a composite of new or worsening nephropathy or new or worsening retinopathy. Patients with a higher baseline heart rate were at increased risk of a new major microvascular complication during follow-up (adjusted hazard ratio: 1.13 per 10 beats per minute; 95% confidence interval: 1.07–1.20; P<0.001). The excess hazard was evident for both nephropathy (adjusted hazard ratio: 1.16 per 10 beats per minute; 95% confidence interval: 1.08–1.25) and retinopathy (adjusted hazard ratio: 1.11 per 10 beats per minute; 95% confidence interval: 1.02–1.21).

Conclusion

Patients with type 2 diabetes mellitus who have a higher resting heart rate experience a greater incidence of new-onset or progressive nephropathy and retinopathy.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00145925. http://www.advance-trial.com/static/html/prehome/prehome.asp

Hypotensive and heart rate-lowering effects in rats receiving milk fermented by specific Lactococcus lactis strains

Previous studies have demonstrated that milk fermented by specific Lactococcus lactis strains significantly inhibits the activity of angiotensin I-converting enzyme (ACE). However, the relationship between the ACE inhibitor and its in vivo action has revealed discrepancies. Therefore, the aim of the present study was to investigate the antihypertensive and heart rate (HR)-lowering effect of milk fermented by specific L. lactis in a murine model. Spontaneously hypertensive male rats (271 (SD14) g) were randomised into four treatment groups that were orally administered with milk fermented by L. lactis NRRL B-50 571 or L. lactis NRRL B-50 572 at 35 or 50 mg protein/kg body weight (BW), respectively. Further, two more groups were fed with different solutions as controls: a saline solution as the negative control and Captopril™ (40 mg/kg BW), a proven ACE inhibitor, as the positive control. Blood pressure and HR were monitored by the tail-cuff method before the treatments and at 2, 4, 6 and 24 h post-oral administration. The results demonstrated that milk fermented by L. lactis NRRL B-50 571 as well as by L. lactis NRRL B-50 572 presented an important systolic and diastolic blood pressure- and HR-lowering effect. Thus, milk fermented by specific L. lactis strains may present potential benefits in the prevention and treatment of CVD associated with hypertension in humans.

[Heart rate and rate control : Prognostic value in cardiovascular diseases]

Resting heart rate represents a cardiovascular risk indicator and an important target of therapy in chronic heart failure and potentially in coronary artery disease. Clinical and experimental evidence suggests that sustained elevation of heart rate - independent of the underlying trigger - plays a causal role in the pathogenesis of vascular disease. Results of the SHIFT trial support the importance of heart-rate reduction with ivabradine for improvement of clinical outcomes in heart failure and confirm the role of heart rate as a risk factor for patients with severe left ventricular dysfunction. Results of the BEAUTIFUL trial show that patients with ischemic heart disease and a heart rate above 70 bpm exhibit an adverse prognosis concerning coronary events.

Genetic locus on mouse chromosome 7 controls elevated heart rate

Elevated heart rate (HR) is a risk factor for cardiovascular diseases. The goal of the study was to map HR trait in mice using quantitative trait locus (QTL) analysis followed by genome-wide association (GWA) analysis. The first approach provides mapping power and the second increases genome resolution. QTL analyses were performed in a C3HeB×SJL backcross. HR and systolic blood pressure (SBP) were measured by the tail-cuff plethysmography. HR was ∼80 beats/min higher in SJL compared with C3HeB. There was a wide distribution of the HR (536-763 beats/min) in N2 mice. We discovered a highly significant QTL (logarithm of odds = 6.7, P < 0.001) on chromosome 7 (41 cM) for HR in the C3HeB×SJL backcross. In the Hybrid Mouse Diversity Panel (58 strains, n = 5-6/strain) we found that HR (beats/min) ranged from 546 ± 12 in C58/J to 717 ± 7 in MA/MyJ mice. SBP (mmHg) ranged from 99 ± 6 in strain I/LnJ to 151 ± 4 in strain BXA4/PgnJ. GWA analyses were done using the HMDP, which revealed a locus (64.2-65.1 Mb) on chromosome 7 that colocalized with the QTL for elevated HR found in the C3HeB×SJL backcross. The peak association was observed for 17 SNPs that are localized within three GABA(A) receptor genes. In summary, we used a combined genetic approach to fine map a novel elevated HR locus on mouse chromosome 7.

Resting heart rate and the risk of death and cardiovascular complications in patients with type 2 diabetes mellitus

AIMS/HYPOTHESIS

An association between resting heart rate and mortality has been described in the general population and in patients with cardiovascular disease. There are, however, few data exploring this relationship in patients with type 2 diabetes mellitus. The current study addresses this issue.

METHODS

The relationship between baseline resting heart rate and all-cause mortality, cardiovascular death and major cardiovascular events (cardiovascular death, non-fatal myocardial infarction or non-fatal stroke) was examined in 11,140 patients who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) Study.

RESULTS

A higher resting heart rate was associated with a significantly increased risk of all-cause mortality (fully adjusted HR 1.15 per 10 bpm [95% CI 1.08, 1.21], p<0.001), cardiovascular death and major cardiovascular outcomes without adjustment and after adjusting for age and sex and multiple covariates. The increased risk associated with a higher baseline resting heart rate was most obvious in patients with previous macrovascular complications (fully adjusted HR for death 1.79 for upper [mean 91 bpm] vs lowest [mean 58 bpm] fifth of resting heart rate in this subgroup [95% CI 1.28, 2.50], p = .001).

CONCLUSIONS/INTERPRETATION

Among patients with type 2 diabetes, a higher resting heart rate is associated with an increased risk of death and cardiovascular complications. It remains unclear whether a higher heart rate directly mediates the increased risk or is a marker for other factors that determine a poor outcome.

The biological effects of ivabradine in cardiovascular disease

A large number of studies in healthy and asymptomatic subjects, as well as patients with already established cardiovascular disease (CAD) have demonstrated that heart rate (HR) is a very important and major independent cardiovascular risk factor for prognosis. Lowering heart rate reduces cardiac work, thereby diminishing myocardial oxygen demand. Several experimental studies in animals, including dogs and pigs, have clarified the beneficial effects of ivabradine associated with HR lowering. Ivabradine is a selective inhibitor of the hyperpolarisation activated cyclic-nucleotide-gated funny current (If) involved in pacemaker generation and responsiveness of the sino-atrial node (SAN), which result in HR reduction with no other apparent direct cardiovascular effects. Several studies show that ivabradine substantially and significantly reduces major risks associated with heart failure when added to guideline-based and evidence-based treatment. However the biological effect of ivabradine have yet to be studied. This effects can appear directly on myocardium or on a systemic level improving endothelial function and modulating immune cell migration. Indeed ivabradine is an 'open-channel' blocker of human hyperpolarization-activated cyclic nucleotide gated channels of type-4 (hHCN4), and a 'closed-channel' blocker of mouse HCN1 channels in a dose-dependent manner. At endothelial level ivabradine decreased monocyte chemotactin protein-1 mRNA expression and exerted a potent anti-oxidative effect through reduction of vascular NADPH oxidase activity. Finally, on an immune level, ivabradine inhibits the chemokine-induced migration of CD4-positive lymphocytes. In this review, we discuss the biological effects of ivabradine and highlight its effects on CAD.

Effect of changing heart rate during treatment of hypertension on incidence of heart failure

An elevated heart rate (HR) at rest at baseline is associated with an increased risk of incident heart failure (HF) and with greater cardiovascular event rates in patients with chronic HF. However, despite the high attributable risk of hypertension for HF, whether the in-treatment HR predicts incident HF in patients with treated hypertension has not been evaluated. The HR was evaluated on annual electrocardiograms from 9,024 patients with hypertension without HF who were treated with losartan- or atenolol-based regimens. During a mean follow-up of 4.7 ± 1.1 years, HF developed in 285 patients (3.2%). On multivariate Cox analyses adjusted for randomized treatment, the baseline risk factors for HF, baseline and in-treatment blood pressure, QRS duration, and electrocardiographic left ventricular hypertrophy, a greater in-treatment HR predicted a 45% greater adjusted risk of new HF for every 10-beats/min increase in the HR (95% confidence interval [CI] 34% to 57%) or a 159% greater risk of HF in patients with the persistence or development of a HR of ≥84 beats/min (95% CI 88% to 257%). In contrast, with adjustment for the same covariates, the baseline HR as a continuous variable was a significantly less powerful predictor of new HF (hazard ratio 1.15 per 10 beats/min, 95% CI 1.03 to 1.28) and a baseline HR of ≥84 beats/min did not predict new HF (hazard ratio 1.00, 95% CI 0.63 to 1.58). In conclusion, a greater in-treatment HR on the serial electrocardiograms predicts a greater risk of incident HF during antihypertensive treatment, independent of the covariates, in patients with hypertension with electrocardiographic left ventricular hypertrophy. These findings support serial HR assessment to improve the risk stratification of patients with hypertension.

31st g. Heiner sell lectureship: secondary medical consequences of spinal cord injury

Persons with spinal cord injury (SCI) have secondary medical consequences of paralysis and/or the consequences of extreme inactivity. The metabolic changes that result from reduced activity include insulin resistance with carbohydrate disorders and dyslipidemia. A higher prevalence of coronary artery calcification was found in persons with SCI than that in matched able-bodied controls. A depression in anabolic hormones, circulating testosterone and growth hormone, has been described. Adverse soft tissue body composition changes of increased adiposity and reduced skeletal muscle are appreciated. Immobilization is the cause for sublesional disuse osteoporosis with an associated increased risk of fragility fracture. Bowel dysmotility affects all segments of the gastrointestinal tract, with an interest in better defining and addressing gastroesophageal reflux disease and difficulty with evacuation. Developing and testing more effective approaches to cleanse the bowel for elective colonoscopy are being evaluated. The extent of respiratory dysfunction depends on the level and completeness of SCI. Individuals with higher spinal lesions have both restrictive and obstructive airway disease. Pharmacological approaches and expiratory muscle training are being studied as interventions to improve pulmonary function and cough strength with the objective of reducing pulmonary complications. Persons with spinal lesions above the 6th thoracic level lack both cardiac and peripheral vascular mechanisms to maintain blood pressure, and they are frequently hypotensive, with even worse hypotension with upright posture. Persistent and/or orthostatic hypotension may predispose those with SCI to cognitive impairments. The safety and efficacy of anti-hypotensive agents to normalize blood pressure in persons with higher level cord lesions is being investigated.

Comparison of 24-hour cardiovascular and autonomic function in paraplegia, tetraplegia, and control groups: implications for cardiovascular risk

BACKGROUND

Fluctuations in 24-hour cardiovascular hemodynamics, specifically heart rate (HR) and blood pressure (BP), are thought to reflect autonomic nervous system (ANS) activity. Persons with spinal cord injury (SCI) represent a model of ANS dysfunction, which may affect 24-hour hemodynamics and predispose these individuals to increased cardiovascular disease risk.

OBJECTIVE

To determine 24-hour cardiovascular and ANS function among individuals with tetraplegia (n=20; TETRA: C4-C8), high paraplegia (n=10; HP: T2-T5), low paraplegia (n=9; LP: T7-T12), and non-SCI controls (n=10). Twenty-four-hour ANS function was assessed by time domain parameters of heart rate variability (HRV); the standard deviation of the 5-minute average R-R intervals (SDANN; milliseconds/ms), and the root-mean square of the standard deviation of the R-R intervals (rMSSD; ms). Subjects wore 24-hour ambulatory monitors to record HR, HRV, and BP. Mixed analysis of variance (ANOVA) revealed significantly lower 24-hour BP in the tetraplegic group; however, BP did not differ between the HP, LP, and control groups. Mixed ANOVA suggested significantly elevated 24-hour HR in the HP and LP groups compared to the TETRA and control groups (P<0.05); daytime HR was higher in both paraplegic groups compared to the TETRA and control groups (P<0.01) and nighttime HR was significantly elevated in the LP group compared to the TETRA and control groups (P<0.01). Twenty-four-hour SDANN was significantly increased in the HP group compared to the LP and TETRA groups (P<0.05) and rMSSD was significantly lower in the LP compared to the other three groups (P<0.05). Elevated 24-hour HR in persons with paraplegia, in concert with altered HRV dynamics, may impart significant adverse cardiovascular consequences, which are currently unappreciated.